Reproductive Factors and Subtypes of Breast Cancer Defined by Estrogen Receptor, Progesterone Receptor, and Human Epidermal Growth Factor Receptor 2: A Register-Based Study From Korea

Accepted Manuscript Reproductive factors and subtypes of breast cancer defined by ER,PR,and HER-2: a register-based study from Korea Lee Jung Sun, Minkyung Oh PII:

S1526-8209(14)00106-2

DOI:

10.1016/j.clbc.2014.05.003

Reference:

CLBC 282

To appear in:

Clinical Breast Cancer

Received Date: 9 December 2013 Revised Date:

15 May 2014

Accepted Date: 27 May 2014

Please cite this article as: Sun LJ, Oh M, , Reproductive factors and subtypes of breast cancer defined by ER,PR,and HER-2: a register-based study from Korea, Clinical Breast Cancer (2014), doi: 10.1016/ j.clbc.2014.05.003. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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1) Title: Reproductive factors and subtypes of breast cancer defined by ER,PR,and HER-2: a register-based study from Korea

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2) Authors: Lee Jung Sun1, Minkyung Oh2, The Korean Breast Cancer Society 3) Affiliations: Department of Surgery1, Haeundae paik Hospital, College of Medicine, University of Inje. Department of Pharmacology2, College of Medicine, University of Inje, Clinical Trial Center.

4) All funding sources supporting publication of a work or study: Funding for the study resources was provided

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by the University of Inje in 2013.

5) Running title: Reproductive factors , breast cancer survival, breast cancer subtypes

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6) Corresponding author: Jung Sun Lee, M.D., Ph.D.

Address: #1435, Jwa-dong, Haeundae-gu, Busan, Korea, Zip-code: 612-030 Telephone: 82-51-797-0695 E-mail: [email protected]

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Fax:82-51-895-1864

7) Number of Words/ Characters in abstract and manuscript 243/1425 in abstract

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2865/16041 in maniscript

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Competing interests MKO performed the statistical analysis under the supervision of JSL, and JSL wrote the manuscript. All authors

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have read and approved the final manuscript. The author(s) declare that they have no competing interests.

MicroAbstract

Through a large sized registry- based study, we reported the correlation between the reproductive factor of

(≥4)

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breast cancer risk and breast cancer outcome according to breast cancer subtypes by IHC analysis. High parity or early AFB(<20) were correlated with worse clinical outcomes in luminal breast cancer patients, but

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were not with other subtyped breast cancers. It highlighted distinctive effects on each subtyped breast cancer. Abstract

Background: The relationship between reproductive breast risk factors and breast cancer survival in patients with different breast cancer subtypes were not well known. Patients and Methods: We examined a large sized retrospective study of 23,882 subjects from the Korean Breast Cancer Registry. The breast cancer subtype was determined by immunohistochemical staining for the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Information regarding reproductive factors, including

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breastfeeding, age at first birth (AFB), and parity, was gathered. Multivariate Cox regression analysis was used to estimate the association between breast cancer subtypes, such as luminal A, luminal B, Her-2/neu overexpressing, and Triple negative breast cancer (TNBC) and breast cancer survival as dependent variables and adjusting for age and stage. Results: High parity(≥5) increased recurrence risk of luminal A and B breast cancer

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(HR=1.95, 95% CI: 0.96-3.97, p=0.0055), (HR=1.12, 95% CI: 0.42-3.02, p=0.0073) in breast cancer specific survival, but one to three child births decreased recurrence risk of luminal A(HR=0.56, 95% CI: 0.34-0.91, p=0.0055) or B breast cancer (HR=0.32, 95% CI: 0.17-0.61, p= 0.0073) in breast cancer specific survival. Early luminal A breast cancers (HR=1.61, 95% CI:0.62-4.26, p=0.039) in

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AFB (<20) increased recurrence risk of

breast cancer specific survival and of TNBCS (HR=1.31, 95%CI:0.78-2.21,p=0.0006) in overall survival. Her2/neu overexpressing breast cancer had no correlation with parity, and AFB in breast cancer survival. Conclusion: High parity (≥5) or early AFB(<20) were correlated with worse clinical outcomes in luminal breast cancer patients, but were not with other subtyped breast cancers. Keywords: Reproduction, Breast cancer survival, Breast feeding, Breast cancer subtype Abbreviations

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AFB Age at first birth HR Hazard ratios BCSS Breast cancer-specific survival

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OS Overall survival HER2 Her-2/neu expression ER Estrogen receptor

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PR Progesterone receptor

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TNBC Triple negative breast cancer

Introduction

Breast and cervical cancers are the most common cancers in women. Moreover, due to the rapid societal and economic transitions that have occurred in many countries, any reduction in infection-related cancers has been offset by an increasing number of new cases associated with reproductive, dietary, and hormonal factors. 1While

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the factors that affect the risk of breast cancer are diverse and not limited to reproductive history, 2 the aging of the population and low fertility rates suggest that women play an indispensable role in the work force, which inevitably favors the delay of the first birth, low parity, and a shorter duration of breast feeding. Because reproductive risk factors associate strongly with incidence, it is possible that they also influence prognosis, perhaps via a hormone-induced growth stimulation pathway. However, the influence of the age at first birth

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(AFB), parity, and breastfeeding on breast cancer survival is not yet clear. Previous studies suggest that high parity may affect survival by promoting the production of more aggressive tumors, 3-6 but another study failed to confirm this finding. 7 There are also conflicting reports in relation to the AFB; some studies reported no

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association,8 while others reported that a higher AFB was associated with either better 9,10 or worse 11survival. In addition, almost all studies evaluating the relationship between reproductive factors and breast cancer survival have grouped all breast cancer cases together, although different subtypes of breast cancer may differ in their susceptibility to various factors and etiologies and thus may have inherently different prognoses. 12,13 Breast cancer has been classified into five clinically relevant subtypes based on the immunohistochemical analysis of ER, PR, and HER2 expression: luminal A, luminal B, HER2-overexpressing, basal-like, and normal breast-like (unclassified). 14 Of these subtypes, basal-like tumors express low levels of ER-related genes and

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HER2 genes; in other words, clinically , there are often ER-,PR-and HER2-, triple negative breast cancer(TNBC).15,16 In the present study, we hypothesized that reproductive events associated with increased ER levels may influence the prevalence of breast tumors, especially the luminal A or B subtypes that express the ER. The identification and validation of these breast cancer subtypes has significantly shifted the approach to this

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provide insight into how tumor differences influence survival after breast cancer.

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complex disease, and further understanding of how reproductive factors relate to breast cancer subtypes will

Methods Study population

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Patients diagnosed with breast cancers that were registered in the Korean Breast Cancer Society Registry between January 1993 and December 2009 were studied retrospectively. In total, 29,167 patients were registered by 102 general hospitals, including 41 university hospitals and 61 surgical training hospitals. The database provided information about sex, age, type of operation, stage according to 6th American Joint Committee on Cancer (AJCC) classification, histological findings and the presence of biological markers, adjuvant therapy,

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survival, and cause of death, which was obtained from the Ministry of Health and Welfare, Republic of Korea. The Korean Breast Cancer Society Registry has been described in detail elsewhere.17 The following exclusion criteria were used: (a) male, (b) the ER, PR, and/or HER2 status and T stage were not available, and (c)

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reproductive data were not available . Personal interviews conducted with each patient at the time of his/her diagnosis generated information about each subject, including age, demographic information, reproductive variables (age at menarche, pregnancy, and childbirth; breast feeding; AFB; use of oral contraceptives; and use of hormone-replacement therapy). Participants were considered to be postmenopausal if they reported that their menstrual cycles had stopped for at least 12 months prior to their breast cancer diagnosis. BMI (body mass index) was calculated using the weight at diagnosis and the reported maximum height. Hormone replacement therapies were defined as never, former use, or current use. The tumor characteristics at the time of diagnosis (tumor size, histology, stage, and ER, PR, and HER2 expression) were obtained from pathology reports in

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23,854 of the patients who were registered in the cancer registry database. The tumors were staged according to the TMN stage system, which follows the AJCC criteria and involves the assignment of appropriate letters or numbers to the following three fields: T (primary tumor), N (nodal involvement), and M (distant metastasis).18 This classification was recorded for both clinical and pathological staging. ER and PR expression were recorded as either negative or positive, while for HER2 status, either0, 1+, or 2+ was considered to be negative, and 3+

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was considered to be positive. 19 Reliable Ki-67 labeling index assessment was not available in these period. The breast cancer samples were categorized into breast cancer subtypes on the basis of their immunohistochemical ER, PR, and HER2 status as follows. Luminal A tumors were ER+ and/or PR+ and HER2-; luminal B tumors

were ER+ and/or PR+ and HER2+; HER2-overexpressing tumors were ER-, PR-, and HER2+; and TNBC were

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ER-, PR-, and HER2-. Statistical analyses

The associations between the four breast cancer subtypes (luminal A, luminal B, HER2-overexpressing, and

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TNBC) and patient characteristics (including reproductive/hormonal and family history variables) and tumor characteristics were determined using the chi square test. Multivariate Cox proportional hazard models were used to determine the effect of reproductive factors on the BCSS (or deaths due to breast cancer) and OS (deaths from any cause) rates as dependent variables and adjusting for age and stage. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for the following study factors: age at diagnosis (<35, 35–49, and ≥50); AFB (<20 years, 20–24 years, 25-29 years, >35 years); number of children prior to diagnosis (0,

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1,2,3,4,≥5); and breast feeding history in parous women (never, ever). We also assessed whether the associations of these factors displayed linear trends in relation to breast cancer, as expressed by p-values for trend. We used multiple corrections by a Bonberroni correction.

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All analyses were performed using SAS version 8.2 (SAS institute Inc., Cary, NC, USA).

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Results Associations between breast cancer subtypes and the reproductive, hormonal, and tumor characteristics of

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the patients

In total, 23,854 patients with sub-typed primary breast cancer were enrolled in the present retrospective study and classified into one of the four definitive subtypes. The patients with TNBC were somewhat younger, while

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the patients with Her-2/neu overexpressing breast cancer were somewhat older (p<0.0001) (Table 1). The patients Her-2/neu overexpressing breast cancer were more likely to be postmenopausal than the patients with either luminal A or B breast cancer (p<0.0001). Overall, the luminal A and TNBC breast cancers were smaller and less likely to have nodal involvement (Table 1).

The chi square tests revealed that the breast cancer subtypes associated in different ways with the reproductionrelated breast cancer risk factors (Table 1). The luminal A subtypes tended to associate with late first birth (p<0.0001) (Table 1). Luminal B associated with null parity, while Her2-/neu overexpressing breast cancer

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associated with high parity (≥ 5) (p<0.0001). Furthermore, Her-2/neu overexpressing breast cancer tended to be associated with breast feeding (p<0.0001) and hormone-replacement therapy (P<0.0003), and TNBC were associated with obesity ( BMI>30) (p<0.0001) (Table 1). Relationship between reproductive factors and survival according to breast cancer subtype

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High parity(≥5) increased recurrence risk

of luminal A and B breast cancer (HR=1.95, 95% CI: 0.96-3.97,

p=0.005), (HR=1.12, 95% CI: 0.42-3.02, p=0.007) in breast cancer specific survival, but one to three child births decreased recurrence risk of luminal A(HR=0.56, 95% CI: 0.34-0.91, p=0.005) or B breast cancer

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(HR=0.32, 95% CI: 0.17-0.61, p= 0.007) in breast cancer specific survival. It also increased recurrence risk of luminal A( HR=1.14, 95%CI:0.96-2.05, p<0.0001) or TNBC(HR=1.06, 95%CI:0.68-1.66, p=0.016) in overall survival (Table 2). A mean follow up duration was 7.5(±2.25) years. Early AFB (<20) increased recurrence risk of luminal A breast cancers (HR=1.61, 95% CI:0.62-4.26, p=0.039) in breast cancer specific survival and

of TNBCS (HR=1.31, 95%CI:0.78-2.21,p=0.001) in overall survival.

But AFB with more than 20 years, including more than 30 years, decreased recurrence risk of luminal A or B breast cancer patients in breast cancer specific survival or overall survival. Her-2/neu overexpressed breast cancer did not have significant correlations with parity, and AFB in breast cancer survival (Table 3). A mean

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follow up duration was 7.5(±2.1) years. Breast feeding had no effects on BCSS or OS in all breast cancer

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subtypes(Table 4).

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Discussion

Only a handful of published studies have evaluated how reproductive factors may be differentially associated with the risk of different molecular subtypes of breast cancer. Furthermore, some of these reports specifically

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focused on young women (35-44 years of age), 20, 21 and the remainder either did not stratify the results by age or menopausal status 22,23 or only included postmenopausal women.24 Moreover, in contrast to the current study, these previous reports generally assessed data from a population-based case control study. As expected, luminal A tumors were associated with many reproductive risk factors, namely late AFB(≥30) and luminal B tumors associated with null parity. Unexpectedly, the hormone-negative subtypes of breast cancer were also associated with several of these hormonal factors, such as breastfeeding, hormone replacement

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therapy, and obesity. Other studies have also shown that the risk of developing basal-like breast cancer is increased as a result of obesity and being overweight, particularly in premenopausal women, and that the risk of developing HER2-overexpressing tumors is increased as a result of older age and the use of hormone replacement therapy.13,24, 25Together, these findings suggest that while many of the classical reproductive risk factors associate with luminal A or B breast cancers, the other subtypes also have correlations with reproductive

Parity

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risk factors.

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Anderson et al.26found that participants who had experienced childbirth had an increased 10-year survival rate in comparison to nulliparous women (92% vs. 76% survival; P=0.002). However, parity is not always beneficial, as the protective effect appears to be counteracted by high parity, where higher parity associates with increased cardiovascular and ischemic heart disease mortality.3,10, 27 However, these results are consistent with those of two follow-up studies of breast cancer patients, which had shown that, compared to nulliparous women, increased parity (four or more births) was associated with increased all-cause mortality.28,29However, another study failed to confirm this finding .30 It has also been suggested that high parity may have a protective effect on small and low-grade tumors, with the possible

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consequence that women with high parity may tend to have a relatively advanced and aggressive disease. Parityrelated functional and morphological changes to breast tissue have been evaluated, and the gene expression signature and differentiation-related chromatin remodeling of breast tissue in parous women were distinct from those of nulliparous women.31 Furthermore, a prolonged suppressive effect on carcinogen-induced mammary

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tumor formation was observed following the administration of hCG in rats32, indicating that the high progesterone conditions induced by hCG may be essential to pregnancy-associated breast development, presumably as a result of mammary epithelial stem cell expansion .33 AFB

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A recent cohort study of postmenopausal women with breast cancer in Sweden revealed that both late age at first pregnancy and null parity were associated with increased tumor expression of proteins indicative of

relatively aggressive tumor behavior. 11, 34 These present findings are consistent with those of Kroman et al.7,

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who found that breast cancer survivors who were 25–29 years old at the first childbirth had a 20% reduced risk of all-cause mortality. Moreover, other investigators have also found that patients with an early AFB generally have a poorer prognosis; for example, an early AFB of <20 years was associated with borderline significant decreased survival compared to women whose first births were later.5, 9, 30 However, most other studies examining this issue have not been able to identify an association between AFB and breast cancer prognosis.35-37 Laboratory evidence suggests that, compared to nulliparous women, parous women with an early AFB have long-term changes in the expression of genes that may be involved in breast cancer pathogenesis, such as genes

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involved in cell proliferation and DNA repair. 38 Another potential explanation for our observation relates to differences in socioeconomic status, as women with a high socioeconomic status have been shown to delay childbirth more often than women with a low socioeconomic status. In addition, women with a high socioeconomic status may also have better access to healthcare and cancer treatment, which are important

Breastfeeding

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determinants of breast cancer outcomes.

The effect of breastfeeding on cancer survival has not been studied extensively, and most of the existing

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research on this topic was not based on prospectively collected information.4,10,39 Some studies on breastfeeding that also evaluated ER status reported that breastfeeding may be associated with a reduced risk of developing both ER-positive and -negative tumors.40,41 Thus, our findings indicate that breastfeeding did not make different influences on the survival depending on the breast cancer sub-type, although this result is consistent with the observations of other studies on breastfeeding .4, 10, 11 Study limitations

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Subtypes defined according to clinicopathological criteria are similar to, but not identical to, intrinsic subtypes and represent a convenient approximation. Immunohistochemistry-based sub-typing is typically performed using the definitions adopted by the 2011 St. Gallen Consensus Panel, but the current study was unable to use Ki-67 as a marker.14,19,42-45A number of other studies have evaluated the associations between reproductive

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factors and breast cancer subtypes using immunohistochemical markers, such as ER, PR, and Her-2/neu.22,24,46,47 Furthermore, in the current study, immunohistochemistry was carried out in different laboratories using different methods for both staining and scoring, which may have led to some misclassification of tumor subtypes.

Another limitation of this follow-up study was its reliance on prediagnostic exposure information that was

collected shortly after diagnosis, as well as the fact that these data did not include information on nonclinical

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factors after diagnosis. While this situation is likely not an issue for many of the reproductive variables of

interest (e.g., few women become pregnant after a diagnosis of breast cancer), potential confounders (e.g., socioeconomic position and employment) can change over time, and this effect may reduce the control of such

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factors and make the resultant biases difficult to predict. In addition, data on other variables, such as psychosocial support, other chronic medical disease, and stress, were not collected. The established relationship between estrogen levels and both breast tissue proliferation and breast cancer risk lends biological plausibility to the hypotheses and findings presented here. Pregnancy and other reproductive events are known to substantially affect estrogen and other hormone exposures.48 Therefore, it is biologically plausible that reproductive events may influence the progression of different breast cancer subtypes, especially the luminal types, via a hormonal pathway. The biological mechanisms through which an early AFB or null

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parity could preferentially confer lower survival for luminal A, and B are largely unknown. Breast cancer in Korean women has distinct characteristics different from Caucasian breast cancer, possibly as a result of genetic differences between the races. The incidence of breast cancer is still low in Korea, similar to most other Asian countries, while breast cancer is the most frequent cancer in women, and its incidence is increasing rapidly.49,50 The age distribution is also different than in western countries: the median age at

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diagnosis in Korean women is 45 years, ~ 15 years younger than American women; 9.5-12% of Korean breast cancers develop before the age of 35, which is much higher than in Western countries.51,52

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In conclusion, the unique characteristics of different breast cancer subtypes, along with the considerable variability in their prognoses, suggest that they likely have unique etiologies but that reproductive factors showed different effects on the relationships between individual subtypes and survival. This study also showed that well-established risk factors may have different effects on the disease process of different breast cancer subtypes.

Acknowledgments We gratefully acknowledge the support and assistance of Dr. Ahn and his staff at the Asan Medical Center, as well as the following staff members from the participating Korean Breast Cancer Registry Program: S.H. Ahn,

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J.W. Bae, Y.T. Bae, J.W. Baek, J.G. Bong, K.H. Cha, E.S. Chang, I.T. Chang, S.S. Chang, J.W. Cho, S.H. Cho, Y.U. Cho, J.W. Choi, K.J. Choi, M.S. Choi, S.I. Choi, S.Y. Choi, G.S. Goo, S.H. Han, W. Han, S.J. Hong, J.Y. Hwang, T.I. Hyun, Y.J. Jegal, M.G. Im, Y.G. Joh, S.Y. Jun, B.W. Jung, J. Jung, J.H. Jung, K.H. Jung, P.J. Jung, S.H. Jung, S.S. Jung, Y.H. Jung, Y.S. Jung, D.H. Kang, H.J. Kang, Y.I. Kang, Y.J. Kang, J.H. Keum, D.Y. Kim,

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H.J. Kim, J.G. Kim, J.H. Kim, J.S. Kim, J.S. Kim, K.C. Kim, S.C. Kim, S.H. Kim, S.I. Kim, S.J. Kim, S.W. Kim, S.W. Kim, S.Y. Kim, S.Y. Kim, Y.S. Kim, B.K. Ko, S.S. Ko, S.H. Koh, B.H. Koo, J.Y. Koo, B.S. Kwak, C.H. Lee, C.H. Lee, D.H. Lee, D.S. Lee, E.S. Lee, G.S. Lee, H.D. Lee, H.S. Lee, J.C. Lee, J.H. Lee, J.K. Lee,

J.S. Lee, J.Y. Lee, K.M. Lee, K.P. Lee, K.S. Lee, K.Y. Lee, M.H. Lee, R.A. Lee, S.C. Lee, S.J. Lee, S.K. Lee, W. Lee, Y.H. Lee, J.W. Leu, C.H. Lim, C.W. Lim, B.I. Moon, Y.S. Nam, S.J. Nam, D.Y. Noh, W.C. Noh, S.J. Oh, S.S. Oh, W.K. Pae, I.W. Paik, N.S. Paik, B.G. Park, B.W. Park, C.H. Park, H.B. Park, H.Y. Park, J.H. Park,

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K.H. Park, S.J. Park, S.T. Park, S.W. Park, W.C. Park, Y.K. Park, Y.K. Park, H.S. Seo, K.H. Seo, Y.J. Seo, Y.S. Sin, B.H. Son, G.S. Son, B.J. Song, K.H. Song, Y.J. Song, Y.J. Suh, J.M. Won, D.H. Woo, D.H. Yang, J.H.

Clinical Practice Points

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Yang, K.Y. Yoo, S.Y. Yoo, H.S. Yoon, J.H. Yoon, and S.O. Yoon.

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1. High parity (≥5) showed worse clinical outcomes in luminal cancer patients 2. One or three child births showed good clinical outcome in luminal breast cancer or TNBC

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3. Early AFB(< 20) increased the HR of BCSS in luminal A breast cancers, and the HR of OS in TNBCs, but AFB with more than 20 years decreased the HR of BCSS or OS in luminal breast cancers 4. Her-2/neu overexpressing breast cancers had no correlation with parity, and AFB in the breast cancer survival. 5. Breast feeding had no effects on breast cancer survival in all breast cancer subtypes.

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References

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1. Bray F, Jemal A, Grey N, et al. Global cancer transitions according to the human development index (20082030): a population based study. Lancet Oncol 2012; 13: 790-801. 2. Yoshimoto N, Nishiyama T, Toyama T, et al. Genetic and environmental predictors, endogenous hormones

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and growth factors and risk of estrogen receptor positive breast cancer in Japanese women. Cancer Sci 2011; 102:2065-72.

3. Wolff AC, Hammond ME, Schwartz JN, et al. American Society of Clinical Oncology/ College of American Pathologists guideline recommendations for human epidermal growth factor receptor 2 testing in breast cancer. J Clin Oncol 2007; 25:118-45. 4. Whiteman MK, Hillis SD, Curtis KM, et al. Reproductive history and mortality after breast cancer diagnosis. Obstet Gynecol 2004;104:146–54.

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ACCEPTED MANUSCRIPT

5. Greenberg ER, Vessey MP, McPherson K , et al. Body size and survival in premenopausal breast cancer. Br J Cancer 1985;51;691-7. 6. Pike M, Krailo M, Henderson B, et al .‘Hormonal’ risk factors, ‘breast tissue age’ and the age-incidence of

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breast cancer. Nature 1983;303:767-70. 7. Kroman N, Wohlfahrt J, Andersen KW, et al. Parity, age at first childbirth and the prognosis of primary breast cancer. Br J Cancer 1998;78:1529-33.

8. Barnett GC, Shah M, Redman K, et al. Risk factors for the incidence of breast cancer: do they affect survival from the disease? J Clin Oncol 2008;26:3310-16.

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9. Rosenberg L, Thalib L, Adami HO, et al. Childbirth and breast cancer prognosis. Int J Cancer 2004;111;77276.

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10. Trivers KF, Gammon MD, Abrahamson PE, et al. Association between reproductive factors and breast cancer survival in younger women. Breast Cancer Res Treat 2007;103:93–102.

11. Alsaker MD, Opdahi S, Asvold BO, et al. The association of reproductive factors and breastfeeding with long term survival from breast cancer. Breast cancer Res Treat 2011;30:175-82.

12. Blows FM, Driver KE, Schmidt MK, et al. Subtyping of breast cancer by immunohistochemistry to investigate a relationship between subtypes and short and long term survival: a collaborative analysis of data for

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10,159 cases from 12 studies. PLos Med 2010;7:e1000279.

13. Yang XR, Chang-Claude J, Goode EL, et al. Association of breast cancer risk factors with tumor subtypes: a pooled analysis from the breast cancer association consortium studies. J Natl Cancer Inst 2011; 103:250-63. 14. Cheang MC, Chia SK, Voduc D, et al. Ki 67 index,Her-2 status and prognosis of patients with luminal B

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breast cancer. J Natl Cancer Inst 2009;101:736-50.

15. Perou CM, Sorlie T, Eisen MB, et al. Molecular portraits of human breast tumours. Nature 2000; 406:747–

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52.

16. Sorlie T, Perou CM, Tibshirani R, et al. Gene expression patterns of breast carcinomas distinguish tumor subclasses with clinical implications. Proc Natl Acad Sci USA 2001;98:10869–74. 17. Ahn SH, Son BH, Kim SW, et al. Poor outcome of hormone receptor-positive breast cancer at very young age is due to tamoxifen resistance: nationwide survival data in Korea—a report from the Korean Breast Cancer Society. J Clin Oncol 2007;25:2360–8. 18. American Joint Committee on Cancer, Manual for Staging of Cancer. 5th edition. Philadelphia, LippincottRaven Publishers,1997.

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ACCEPTED MANUSCRIPT

19. Hammond ME, Hayes DF, Wolff AC .Clinical notice for American Society of Clinical Oncology-College of American Pathologists guideline recommendations on ER/PgR and HER2 testing in breast cancer. J Clin Oncol 2011;29: e458. 20. Li CI, Beabar EF, Tang MC, et al. Reproductive factors and risk of estrogen receptor positive, triple-

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negative, and HER2-neu overexpressing breast cancer among women 20-44 years of age. Breast Cancer Res Treat 2013;137:579-87.

21. Ma H, Wang Y, Sullivan-Hally J, et al. Use of four biomarkers to evaluate the risk of breast cancer subtypes in the women’s contraceptive and reproductive experience study. Cancer Res 2001; 70:575-87.

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22. Gaudet MM, Press MF, Halie RW, et al. Risk factors by molecular subtypes of breast cancer across a population –based study of women 56 years or younger. Breast Cancer Res Treat 2011;130:587-97.

2008:109;123-39.

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23. Millikan RC, Newman B, Tse CK, et al. Epidemiology of basal-like breast cancer. Breast cancer Res Treat

24. Phipps AI, Malone KE, Porter PL, et al. Reproductive and hormonal risk factors for postmenopausal luminal, Her-3-overexpressing and triple negative breast cancer. Cancer 2008;113:1521-6. 25. Carey LA, Perou CM, Livasy CA, et al. Race, breast cancer subtypes, and survival in the Carolina Breast Cancer Study JAMA 2006;295:2492-502.

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26. Warren Andersen S, Newcomb PA, Hampton JM, et al. Reproductive factors and histologic subtype in relation to mortality after a breast cancer diagnosis. Breast cancer Res Treat 2011;130:975-80. 27. Black M, Hankey B, Barclay T. Parity as a prognostic factors in young breast cancer patients. J Natl Cancer Inst 1983;70:27-30.

28. Largent J, Ziogas A, Anton-Culver H. Effect of reproductive factors on stage, grade and hormone receptor

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status in early-onset breast cancer. Breast Cancer Res 2005;7:R541–R554. 29. Alsaker MD, Opdahi S, Romundstad PR, et al. Association of time since last birth, age at first birth and

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parity with breast cancer survival among parous women: a register-based study from Norway. Int J Cancer 2013;132:174-81.

30. Morinoto Y, Killeen J, Hernandez BY, et al. Parity and expression of epithelial histopathologic markers in breast tissue. Eur J Cancer Prev.2013;22:404-8. 31. Asztalos S, Gann PH, Hayes MK, et al . Gene expression patterns in the human breast after pregnancy. Cancer Prev Res 2010;3:301-11.

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32. Russo IH, Koszalka M, Russo J. Comparative study of the influence of pregnancy and hormonal treatment on mammary carcinogenesis. Br J Cancer 1991;64:481-4. 33. Kobayasi S, Sugiura H, Ando Y, et al. Reproductive history and breast cancer risk. Breast

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Cancer2012;19:302-8. 34. Butt S, Borgquist S, Anagnostaki L, et al. Parity and age at first childbirth in relation to the risk of different breast cancer subgroups. Int J Cancer2009; 125:1926–34.

35. Schouten LJ, Hupperets PS, Jager JJ, et al . Prognostic significance of etiological risk factors in early breast cancer. Breast cancer Res Treat 1997;43;217-23.

SC

36. Barnett GC, Shah M, Redman K, et al. Risk factors for the incidence of breast cancer: do they affect survival from the disease? J Clin Oncol 2008:26; 3310-6.

Epidermiol Biomarkers Prev 2002;11:235-41.

M AN U

37. Daling J, Malone K, Doody D. The relation of reproductive factors to mortality from breast cancer. Cancer

38. Balogh GA, Heulings S, Mailo DA, et al. Genomic signature induced by pregnancy in the human breast. Int J Oncol 2006;28;399-410.

39. Phillips KA, Milne RL, West DW, et al. Prediagnostic reproductive factors and all-cause mortality for women with breast cancer in the breast cancer family registry. Cancer Epidermiol Biomarkers Prev

TE D

2009;18:1792–7.

40. Ma H, Bernstein L, Pike MC, et al. Reproductive factors and breast cancer risk according to joint estrogen and progesterone receptor status: a meta-analysis of epidemiological studies. Breast Cancer Res 2006;8:R43. 41. Trivers KF, Lund MJ, Porter PL, et al. The epidemiology of triple-negative breast cancer including race. Cancer Causes Control 2009;20:1071–82.

EP

42. Goldhirsch A, Wood WC, Coates AS, et al. Strategies for sbutypes- dealing with the diversity of breast cancer: highlights of the St Gallen international Expert Consensus on the primary therapy of early breast cancer 2011.Ann Oncol 2011;22:1736-47.

AC C

43. Viale G, Regan MM, Mastropasqua MG, et al. Predictive value of tumor Ki-67expression in two randomized trials of adjuvant chemoendocrine therapy for node-negative breast cancer. J Natl Cancer Inst 2008;100: 207–12.

44. Viale G, Giobbie-Hurder A, Regan MM, et al.Prognostic and predictive value of centrally reviewed Ki-67 labeling index in postmenopausal women with endocrine-responsive breast cancer: results from Breast International Group trial1-98 comparing adjuvant tamoxifen with letrozole. J Clin Oncol 2008; 26:5569–75. 45. Dowsett M, Nielsen TO, A’Hern R, et al. Ki67 in breast cancer: recommendations from the International Ki67 in Breast Cancer Working Group. J Natl Cancer Inst 2011;103:1656-64.

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46. Kwan ML, Kushi LH, Weltzien E , et al. Epidemiology of breast cancer subtypes in two prospective cohort studies of breast cancer survivors. Breast Cancer Res2009;11:R 31. 47. Turkoz FP, Solak M, Petekkaya I, et al . Association between common risk factors and molecular subtypes

RI PT

in breast cancer patients. Breast 2013;22: 344-50. 48. Pathak DR. Dual effect of first full term pregnancy on breast cancer risk: empirical evidence and postulated underlying biology. Cancer Causes Control 2002;13;295-8.

49. Ahn SH. Clinical characteristics of breast cancer patients in Korea in 2000. Arch Surg 2004;139:27-31.

50.Yoo KY, Kang D, Park SK, et al. Epidemiology of breast cancer in Korea: occurrence, high-risk groups, and

SC

prevention. J Korean Med Sci 2002;17:1-6.

51.Han W, Kim SW, Park IA, et al. Young age: an independent risk factors for disease-free survival in women

M AN U

with operable breast cancer. BMC Cancer 2004;4:82.

52.Han W, Nicolau M, Noh DY, et al. Characterization of molecular subtypes of Korean breast cancer: an

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ethicially and clinically distinct population. Int J Oncol 2010;37:51-9.

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Table 1 Distribution [n(%)] of baseline characteristics ( at diagnosis) among all breast cancer patients Luminal A %

n

Luminal B %

HER n

TNBC

%

Age at diagnosis ( years ) 820 7210 5050

6.27 55.12 38.61

218 1556 946

8.01 57.21 34.78 T stage

204 1195 1486

7.07 41.42 51.51

T1-2

11216

85.75

2251

82.76

2338

T3-4 T0,X

648 1193

4.95 9.12

231 237

261 279

+

73.73

2083

76.58

3436

26.27

637

23.42

8063 5017

61.64 38.36

1525 1195

LN status 56.07 43.93 ER

%

10.8 47.99 41.21

81.04

4512

87.83

9.05 9.67

440 175

8.57 3.41

M AN U

9644

<.0001

66.31

3619

70.45

972

33.69

1518

29.55

1683 1202

58.34 41.66

3177 1960

61.85 38.15

<.0001

<.0001

985

7.53

368

13.54

2885

100

5137

100

+

12092

92.47

2350

86.46

0

0

0

0

EP

-

Age at first birth(years) 232

1.95

20-24

2987

25.07

25-29

5312

44.58

≥30

1445

12.13

46

<.0001

1.82

43

1.63

109

2.37

614

24.34

799

30.33

1303

28.38

1155

45.82

1129

42.85

1875

40.84

258

10.23

263

9.98

514

11.20

AC C

<20

Parity

p-value <.0001

<.0001

1913

TE D

Pre menopausal Post menopausal

8.49 8.71 Menopausal status

n

555 2465 2117

SC

<35 35-49 ≥50

RI PT

n

<.0001

ACCEPTED MANUSCRIPT

1940

14.83

449

16.51

400

13.86

790

15.38

1-2

8224

62.87

1710

62.87

1673

57.99

3062

59.61

≥3

2916

22.29

561

20.63

812

28.15

1285

25.01

Breast feeding 3418

30.16

663

28.64

612

24.97

yes

7916

69.84

1652

71.36

1839

HRT user (%)

945

8.41

169

7.32

255

402

3.27

87

3.37

Average (18.5-24.9)

8280

67.31

1831

70.94

Overweight (25.0-29.9)

3101

25.21

580

22.47

Obese (≥30)

519

4.22

83

80

EP

AC C

3.22

75.03

3051

70.64

10.25

416

9.65

0.0003

<.0001

2.96

159

3.33

1832

67.7

3053

63.88

694

25.65

1318

27.58

100

3.7

249

5.21

TE D

Underweight (<18.5)

29.36

M AN U

BMI (kg/m2 )

<.0001

1268

SC

no

RI PT

Nulliparous

ACCEPTED MANUSCRIPT

Table 2 Breast cancer- specific and overall survival by parity and stratified by breast cancer subtypes

case

events

Luminal B HR(95%CI)

case

events

Her-2 overexpressed HR(95%CI)

Parity

case

Breast cancer specific survival

TNBC

RI PT

Luminal A

events

HR(95%CI)

case

events

HR(95%CI)

21

Ref

790

37

Ref

7

0.391(0.166-0.921)

728

27

0.757(0.461-1.243)

38

0.529(0.310-0.901)

2334

71

0.615(0.413-0.915)

1940

25

Ref

449

19

Ref

400

1

1862

18

0.762(0.416-1.397)

365

6

0.361(0.144-0.905)

341

2

6362

48

0.562(0.346-0.911)

1345

20

0.326(0.174-0.611)

3

1894

20

0.787(0.437-1.418)

409

9

0.524(0.237-1.158)

533

19

0.670(0.360-1.247)

800

18

0.451(0.257-0.792)

4

605

8

1.004(0.453-2.226)

101

5

1.128(0.421-3.021)

163

7

0.826(0.351-1.942)

296

11

0.756(0.386-1.481)

≥5

417

11

1.957(0.963-3.978)

51

0

0.00(-)

116

5

0.820(0.309-2.174)

189

8

0.921(0.429-1.979)

0.007

110

Ref

449

1

1862

83

0.812(0.611-1.080)

365

2

6362

202

0.525(0.416-0.662)

1345

3

1894

77

0.669(0.500-0.895)

4

605

34

≥5

417

36

p-value

<.0001

0.156

0.069

Overall survival

51

Ref

400

45

Ref

790

92

Ref

31

0.669(0.428-1.045)

341

38

1.017(0.660-1.567)

728

76

0.824(0.608-1.117)

EP

1940

83

0.467(0.329-0.662)

1332

124

0.788(0.560-1.109)

2334

203

0.683(0.534-0.874)

409

32

0.644(0.414-1.003)

533

46

0.764(0.506-1.152)

800

74

0.726(0.535-0.986)

0.976(0.664-1.434)

101

14

1.012(0.560-1.830)

163

18

0.954(0.552-1.648)

296

36

0.981(0.667-1.442)

1.410(0.966-2.058)

51

7

0.910(0.412-2.008)

116

17

1.300(0.744-2.271)

189

24

1.065(0.680-1.669)

AC C

Nulliparous

1332

M AN U

0.005

Parity

TE D

p-value

SC

Nulliparous

<0.001

0.247

0.016

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

Table 3 Breast cancer- specific and overall survival by age at first birth (AFB) and stratified by breast cancer subtypes Luminal A case

events

Luminal B HR(95%CI)

case

25

Ref

449

TNBC

events

HR(95%CI)

case

events

HR(95%CI)

<20

232

5

1.631(0.624-4.260)

46

20-24

2987

28

0.722(0.421-1.238)

25-29

5312

38

0.534(0.322-0.885)

≥30

1445

11

0.565(0.278-1.149)

Ref

400

21

Ref

790

37

Ref

1

0.465(0.062-3.472)

43

2

1.013(0.237-4.320)

109

3

0.571(0.176-1.850)

614

8

0.277(0.121-0.632)

799

31

0.723(0.415-1.258)

1303

46

0.714(0.463-1.101)

1156

24

0.468(0.256-0.854)

1129

28

0.466(0.265-0.821)

1875

50

0.542(0.354-0.829)

258

4

0.357(0.121-1.048)

263

6

0.408(0.165-1.011)

514

18

0.718(0.409-1.261)

AC C

0.039

19

EP

1940

p-value

Her-2 overexpressed

case

Breast cancer specific survival

Nulliparous

AFB

HR(95%CI)

TE D

AFB

events

0.018

0.060 Overall survival

0.087

ACCEPTED MANUSCRIPT

110

Ref

449

51

Ref

400

<20

232

15

1.053(0.614-1.806)

46

6

0.920(0.394-2.144)

43

20-24

2987

124

0.701(0.542-0.907)

614

48

0.565(0.381-0.839)

799

25-29

5312

171

0.528(0.416-0.671)

1156

79

0.519(0.365-0.739)

1129

≥30

1445

67

0.768(0.567-1.041)

258

18

0.540(0.316-0.925)

<.0001

0.004

Ref

263

790

92

Ref

4

0.971(0.349-2.701)

109

17

1.318(0.785-2.211)

86

0.911(0.635-1.306)

1303

137

0.823(0.632-1.072)

92

0.703(0.492-1.005)

1875

147

0.611(0.471-0.793)

0.946(0.598-1.495)

514

53

0.827(0.590-1.160)

31 0.255

0.001

M AN U

p-value

45

RI PT

1940

SC

Nulliparous

Table 4 Breast cancer- specific and overall survival by breast feeding and stratified by breast cancer subtypes

case

Luminal B

events

HR (95%CI)

1652 663

case

events

HR (95%CI)

case

TNBC

events

HR (95%CI)

case

events

HR (95%CI)

Breast cancer specific survival

yes

7916

71

1.080 (0.697-1.672)

no

3418

28

Ref

p-value Breast feeding

AC C

0.730

28

0.705 (0.381-1.303)

1839

60

1.439 (0.804-2.574)

3051

100

1.143 (0.784-1.667)

16

Ref

612

14

Ref

1268

37

Ref

EP

Breast feeding

HER

TE D

Luminal A

0.264

0.220

0.486

Overall survival

yes

7916

305

0.903 (0.740-1.101)

1652

121

0.825 (0.604-1.126)

1839

185

1.137 (0.841-1.536)

3051

302

1.096 (0.885-1.357)

no

3418

143

Ref

663

59

Ref

612

55

Ref

1268

117

Ref

p-value

0.314

0.225

0.404

0.399